Gen. Peter Chiarelli, former vice chief of staff for the U.S. Army, says the Army lacks reliable diagnostic tools to screen for mental health.

The killing of 16 Afghan civilians last Sunday is now one of the greatest points of tension between the United States and Afghanistan. U.S. Army Staff Sgt. Robert Bales allegedly killed the civilians in cold blood; those close to him say they were shocked by the news.

According to the Pentagon, Bales had been treated for a traumatic brain injury that he suffered in Iraq in 2010, though the extent of the damage is unclear.

Other information leaked by military officials indicate Bales, who was on his fourth deployment, may have "snapped" under pressure due to possible marital problems or alcohol abuse. Bales' civilian lawyer has cast doubt on those theories.

Screening With Uncertainty

Gen. Peter Chiarelli spent the last couple years of his military career working to help troops returning from combat with invisible wounds of war like post-traumatic stress.

He retired from the military in January, ending a four-decade career as a vice chief of staff of the Army. He is now the CEO of One Mind for Research, a nonprofit organization dedicated to finding cures for brain disorders.

Chiarelli said he could not comment on the specifics of Bales' case, but he tells Weekend Edition host Rachel Martin that the staff sergeant would have been screened before, during and after every deployment.

"I can guarantee you that he was screened, and before he was allowed to redeploy, doctors indicated that he was fit for deployment," Chiarelli says. "Unless the investigation shows something different, this is not uncommon for a force that has been fighting in two separate theaters for over 10 years."

He says what the incident "proves more than anything ... is just how much we don't know." As vice chief, Chiarelli says he was frustrated by not having reliable diagnostic tools to screen for behavioral health issues.

"This was a huge problem for us, and continues to be a problem today," he says.

When it comes to screenings, some are done by a health care provider when a soldier returns home. There are also written surveys.

"I don't trust those as much because soldiers know how to answer those in order to be able to go home to their loved ones and not be caught up in future evaluations," Chiarelli says.

It's also possible, he says, that soldiers know how to game the system in order to be redeployed.

Stamping Out Stigma

But Chiarelli is also careful not to stereotype.

"What worries me when we talk about this, more than anything else, is that there's a tendency to kind of paint a brush across every single soldier, male and female, who has served in Iraq or Afghanistan, and think that they have come back with post-traumatic stress or traumatic brain injury," he says. "That's simply not the case."

Misconceptions can spread into other areas of the veterans' lives, like when they talk to employers. Stigma may make some employers think twice about hiring someone who fought for years in Iraq or Afghanistan.

Balancing between raising awareness and combating stigma can be a tricky task.

"You want to raise awareness, you want people to get the help that they need," Chiarelli says, "but at the same time, you do not want to leave the general public with the idea that everyone is suffering from these traumas."

One tool for cutting the cultural bias is language. Rather than saying "post-traumatic stress disorder," or PTSD, he calls it only "post-traumatic stress."

"I have totally dropped the 'D,' and one of the reasons I've dropped the 'D' is no soldier likes to be told that he has a 'disorder.' The key is to try to get him into treatment," Chiarelli says. "There are very effective treatments available, but if you can't get them inside the doors so they can get that help, they do no good."

The general's position has evolved over his years at war. He says one of his greatest regrets is not putting the name of a soldier who committed suicide on a memorial in his division.

"There was a general belief back then [in 2004, 2005] that individuals that committed suicide did not deserve to be on the same memorials as individuals who had lost their life due to enemy action," he says. "That is a tremendous regret that I have."

While Chiarelli has not reached out to that soldier's family, he hopes "that one day I will do that and right that wrong."

Whose Responsibility?

The commander on the ground, he says, has a responsibility to look out for the mental health of those under his command.

"We all have a responsibility to look for the signs. And the signs are obvious. We know the signs. We've taught the signs. People understand the signs," Chiarelli says.

The signals are high-risk behavior, such as self-medicating with alcohol, anger management, involvement in partner abuse and drug abuse.

"We have a responsibility not just to tell him to get help," he says. "We have a responsibility to ensure that they get the help that they need."

The impact of post-traumatic stress and traumatic brain injury reaches beyond the soldier in need.

"I get upset when people start throwing numbers around about the number of people that are affected. I promise you, all the numbers are far less than the real number," Chiarelli says. "Because for every soldier that's out there that has a family, you multiply that number by the size of their family. That's why we have got to find a way to properly diagnose and treat these diseases."